1,721,104 research outputs found
The role of molecular biology in neurosurgery. Meeting of the Research Committee of the EANS in Hamburg, March 3-5, 1995
No full textUse of intraoperative magnetic resonance Imaging in tailored temporal lobe surgeries for epilepsy
No full textPurpose: We investigated whether intraoperative magnetic resonance imaging (MRI) was able to assess immediately the extent of a tailored temporal lobe resection for epilepsy in comparison to delayed postoperative MRI. The recently proposed concept of an individually tailored procedure, preserving tissue not involved in seizures, leads to a variety of differently shaped resections. Methods: For intraoperative imaging we used a Magnetom Open 0.2 Tesla scanner. Fifty-eight patients undergoing temporal lobe resections for pharmacoresistant epilepsy were investigated. Half of these were nonlesional. All patients had delayed postoperative follow-up scans, which were compared with the intraoperative, postresection images. Results: In 49 (84%) of 58 cases, intraoperative MRI depicted the resection cavity identical to delayed postoperative studies. Complete resection of the visible lesion was primarily proved in 23 of the 29 cases. In two patients with lesions and in one nonlesional case, the resection was extended after intraoperative imaging, thus increasing the rate of total resections in gliomas from 73 to 87%. In four patients, an extension into eloquent areas did not allow complete removal. In the nonlesional cases (n = 29), the extent of tailored temporal resections also could be exactly documented intraoperatively. Conclusions: Intraoperative MRI allowed a reliable evaluation of the localization and extent of resection in epilepsy surgery within the operative procedure. Furthermore, it provided the possibility of an image-based correction of an initially incomplete resection, particularly in lesional cases. In the majority of patients, the intraoperative images would have been able to replace delayed postoperative MRI. However, in 16%, there were postoperative changes in the resection volume
Impact of primary surgery on pituitary function in patients with non-functioning pituitary adenomas - a study on 721 patients
No full textIntroduction. The aim of this study was to define the impact of surgery on pituitary function in a large consecutive series of patients harbouring non-functioning pituitary adenomas. Materials and method. Between December 1982 and December 2000, a total of 822 patients underwent primary surgery in the authors' department. In 721 cases a complete set of endocrinological data was available. Functions of the pituitary-gonadal, pituitary-thyroid and pituitary-adrenal axes were assessed immediately before surgery and again one week, 3 months and 1 year after the operation, utilizing standardized tests and commercially available assays. Results. There was some degree of pre-operative hypopituitarism in 561 (85%) and 53 (86.3%) of the patients belonging to the transsphenoidal and the transcranial groups, respectively. Prior to transsphenoidal [transcranial] surgery, 163 (31%) [34 (55.7%)] of the patients had secondary adrenal deficiency, 463 (76.6%) [49 (89%)] had hypogonadism and 105 (19.1%) [14 (25.4%)] were hypothyroid. Preoperatively, prolactin levels were mildly elevated in 167 patients (25.3%), whereas 1 year after surgery, levels were elevated in only 5 patients. Permanent diabetes insipidus occurred in 4 patients, 2 from the transsphenoidal group (0.3%) and 2 from the transcranial group (3.2%). Following transsphenoidal surgery 110 (19.6%) of patients had normal pituitary function [versus 0% after transcranial surgery], 169 (30.1%) [6 (11.3%)] showed improvement, 274 (48.9%) [49 (73.7%)] had persistent deficits and 8 (1.4%) [8 (15%)] showed deterioration of pituitary function. Discussion. These data indicate that transsphenoidal surgery for non-functioning pituitary adenomas in expert hands is, relatively, far less detrimental to patients compared with transcranial surgery. The latter carries a much greater risk of post-operative deterioration in pituitary function
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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